Fix Y103 command (play_pcm)

* The parameter is the number of times to loop, e.g. Y103,2: will play
  the sound twice. This still does not work on Windows because
  PlaySound() does not support specifying the loop count.
* Get AMSE data size from its header. This fixes audio glitch at the end
  of sounds.

src/sys/nact_sys3.cpp

@@ -942,7 +942,7 @@ void NACT_Sys3::cmd_y()
 			break;
 		case 103:
 			if(pcm_index < MAX_PCM) {
-				mako->play_pcm(pcm[pcm_index], param ? false : true);
+				mako->play_pcm(pcm[pcm_index], param);
 			}
 			break;
 		case 104: